|Year : 1983 | Volume
| Issue : 4 | Page : 317-319
Orbital ultrasonography-a diagnostic tool
Y Dayal, N Verma, IM Bhatia
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
Dr. Rajendra Prasad Centre for ophthalmic Sciences, A.I.I.M.S., New Delhi-110029
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Dayal Y, Verma N, Bhatia I M. Orbital ultrasonography-a diagnostic tool. Indian J Ophthalmol 1983;31:317-9
Orbital pseudotumors are an important cause of unilateral exophthalmos and a significant cause of bilateral proptosis (16% Reese, 1969).
In this study, the ultrasonographic features of orbital inflammatory disease, their follow up on therapy and the differential diagnosis are presented.
| Materials and methods|| |
Twenty six patients were chosen from a series of seventy patients with orbital disease who were examined by ultrasonography.
All patients underwent a routine proptosis work up with appropriate laboratory investigations and radiology (both conventional and CT scanning) and a presumptive diagnosis was made. Ultrasonography was performed using the Kretztechnik 7200 MA and Ophthalmoscan 200 scanning units. Compound, arc, linear and sector scanning was done. Five of these patients were subjected to surgery and the rest put on appropriate medical therapy.
| Observations and discussion|| |
These patients formed 37.1 °o of all examined and were in the first to fourth decades of life.
There were certain common features observed in all patients:
(A) Myositis : The rectus muscles are normally visualized as clear spaces on very high sensitivity settings. Enlargement due to oedema or infiltration causes a rearrangement of connective tissue septae and renders these muscles echogenic at lower sensitivity settings (58 db). Myositis as evidenced by focal, nodular or generalized muscle enlargement was seen in all patients with orbital inflammatory disease [Figure - 1].
The average muscle thickness was 5.72 mm and a decrease in their size on therapy was demonstrated which correlated well with muscle function improvement on repeated Hess charting. In cases of thyroid orbitopathy:
(B) Optic nerve changes : (i) accentuation of the optic nerve sheath (linear), (ii) widening of the optic nerve shadow (angular) (never more than 60° ), (iii) elevation of the optic nerve head (Papilloedema).
The optic nerve is normally an echo free space, however, inflammation of its sheath renders it echogenic. The normal four spike pattern on A scanning which is characteristic of the optic nerve was never lost-which helped differentiate infiltration of the optic nerve by inflammatory products from that by a tumor. The average optic nerve thickness was 6.07 mm and a decrease in size was demonstrable with appropriate therapy
(C) Sclerotenonitis : (i) widening of the normal potential episcleral space into a cresent shaped area (posteriorly) (ii) presence of an echo free interval in the retrobulbar fat complex. (A scan)
In two patients an enormous dilatation of this space to form a serous cyst was observed. This dilatation disappeared on therapy.
(D) Changes in Orbital fat : This is by far the most important set of changes in orbital inflammatory disease and helps differentiate the various causes of this condition. They consist of : (i) widening of the normal retrobulbar fat complex from 150-200% of its normal value, (ii) a decrease in the normal transmitted pulsation (on A & M scanning), (iii) reduced compressibility of the retrobulbar fat complex-a feature more marked in thyroid orbitopathy, (iv) presence of tall spikes with a less echogenic interval seen in micro abscess formation (orbital cellulitis). Angle K=10°sub -30°. (v) areas of increased sound attenuation-with fairly well defined borders- granulomas (seen in 72.7%). Angle K=50° -60° [Figure 3]. (vi) coarsening of the fat pattern (which normally has a fairly regular structure). (B Scan.) [Figure - 1]
All the above changes correlate well with the histology of these tumors. The orbital fat is separated by inflammatory cells and oedema fluid which creates reflecting interfaces and increases the width of the retrobulbar spike complex. When the infiltration is by mucopolysaccharides (thyroid orbitopathy) or fungal hyphae, the attenuation is more rapid. The granuloma represents an area of focal lymphocytic infiltration and this accounts for the greater sound attenuation. With surgery the following observations were made:
Evidently CT scanning and conventional orbital radiology are of limited value in the diagnosis and management of orbital inflammatory disease, the changes being beyond the resolving capacity of instruments available today. Moreover, involvement of the optic nerve is often difficult to decide.
It is often difficult to differentiate lymphomas and lymphosarcomas from orbital inflammatory disease and therefore if a granuloma does not regress with therapy surgical intervention is indicated.
It is to be noted that the regression of changes with therapy are detected first by echography-before clinical changes become evident.
Ultrasonography is thus an important tool in the diagnosis and management of orbital inflammatory lesions. Correct diagnosis in these patients obviates the need for surgery or alternatively helps direct its route.
| Summary|| |
The value of ultrasonography in the diagnosis and management of orbital inflammatory disease is presented.
[Figure - 1]
[Table - 1], [Table - 2], [Table - 3]